Process of producing cyanids



Y ciently Patentedv @Apr; .5, if 1932 PArsuri omca EDWARD J. rnANxn or ,BAYSIDE, N W YORK rnocnss or rnonucme cxAmns No Drawings This invention relates to processes for pro- .duclng cyanlds by the use of calciumcyanamid, or calcium carbid and free nitrogemand has for itsobject to produce cyanlds at lower costs than the processes at present in use, and

also to produce. improvedrcyanid products.

Inmy co-pending application, UtSQ Serial No. 472,482 I have shown a large number of chemical reactions by which: cyanids can be "m formed-fromv calcium cyanamld and a sultable source :of sodium, withor without a reducing agent, or fromccalcium .carbid, free nitrogen and a suitable source ofsodium, with or without carbon. I further describe in the said applicationmethods of carrying out the said reactions at high temperatures, and particularly means for preventing volatile substances, particularly sodium, from per-- manently leaving the-reaction zone, namely by passingv the said volatile substances through linterstices in the incoming cold charge, causing volatilized sodium or sodlum compounds tobe condensed and carrled agaln mto thereaction zone.

means of dealingiwith volatile substances, which may, in certain c'ases,"be more easlly and efliciently carried out than the means de-' gen at about 1250 made available as elementary sodium until. 8

scribed in the said co-pending application.

5 @I have stated in my saidco-pending appli-,

cation, for example, thatthe new cyanidwhich 'Ihave discovered and which I call sodium calcium cyanid, is preferably formed at a temperature above 1400 0., .and is not so efliformed at lower temperatures. It is well-known, however, that. calcium cyanamid decomposes with 51038 of freenitrogen'on be- .ing heated to 1250 0. or higher. In'the V M presence of elementary sodium the products 40 of. decomposition of calcium cyan'amid are lrecombinedlwith sodium at 12 C. and higher, as fast as the calciumcyanamid decomposes. When using, however, as a source of sodium; asodium compound which does, 45 not give up; elementary sodium at thetemperature used as, fast as the calcium cyanamidus decomposed, free nitrogen, will, escape r from thereaction zone and necessarily cor- Y 7 respondingly reducejthe final yield of cyanid. In usingcalcium carbid and ,free nitrogen course, reduced in I have further discovered,*'however,i other I a lication. filed August 25, 1930. ;Serial No. 477,805.

instead of calcium cyanamid a similar diiiiculty is encountered, if the decomposition. of the sodium compound is at a faster rate than nitrogen can be introduced. The yield is, of

proportion to the sodium loss unless the sodium is condensed and'returned to the reaction zone.

I have discovered that such losses of free nitrogen or sodium can be prevented by substantially the same means, that is, to say, by

'introducmg ,thecompound which is decomposed at a relatively too rapid rate in relatively small proportional or slightly larger than ,propor-q 6 tional quantities of the remaining materials 7 required toform the cyanid. I I, g

For example if I wish to carryi-out the reaction: I 1

v Na Ga(CN) +3CO+Ga I find that this cannot be successfully done by mixinga charge in'the proportions indicated by the above equation and simply heat-. ng to ar high temperature an ordinary crucible, for the reason that thee-calcium cyanamld is decomposed with loss ofnitro- (3., while sodium is not 1 similar to the product I desire to make,and

to this highlyheated fused mass suddenly add small portions of the mixture, beneath the surface of the fusedmass, the relatively small quantity of mixture added is almost instantly raised to the temperature of the fused composition products from which the cyanid i is to be formed are recombined as ,cyanid before any of them can escape from the reaction zone. 7 v r Similarly, if I desire, for example tocarry out the reaction: Q v p I CaO N +2NaCN Na Ca (ON) I, find that this cannot be done successfully by merely mixing the calcium carbid and-sod 199 j I quantities into a fused bath of I nearly finished cyanid product containing mass and is decomposed and ithefdemass, become decomposed, and products intermingle with and combine with e invention may depth and to lead in current through the fused mass,

um cyanid, heating to above 1400 C. and passing nitrogen into the fused mass, for the reason that the sodium cyanid is decomposed by the carbid at a temperature of about 1300 C., and loses sodium at a greater rate than the nitrogen can be brought in. If, however, I firstprepare a fused bath, at a temperature of say above 1400 C., preferably of composition similar to that of the roduct I desire to make, and to this highly mixture described, beneath the surface of the fused mass, and add the nitrogen at a rate slightly larger than chemically proportional, the solid materials added are almost instantly raised to the temperature of the fused the resulting the nitrogen before any of them, except the excess of nitrogen, can escape from the reaction zone.

Obviously, it does not make any essential difference whether the relatively small portions of charge are added from the top, sides or bottom of the fused mass, but it is desirable/that they be introduced bodily into the fused mass and not merely on the surface. The essential point is that the change from below the temperature of decomposition of the most easily decomposed ingredient to the temperature of most eflicient cyanid formation shall be so sudden that no one or more of the decomposition products needed to form the cyanid will escape before the other products needed are formed and in a position to recombine as cyanid. Any means of bringing this about will serve the same purpose.

As an example of one way in which my be carried out in practice, may provide a simple electric crucible furnace consisting of a graphite crucible of cylindrical shape, the bottom of which is connected to one terminal of a source of electricenergy, the other terminal being connected to an electrode suspended from above the furnace, the electrode being capable of being lowered into the crucible -.0 any desired electric current to heat the charge by the passage of the current therethrough. Level with the hearth of the crucibleI provide a horizontal, water-cooled channel leading from outside of the furnace to the inside of the crucible. Through this channel by means of a revolving screw fed from a suitable hopper outside of the furnace I introduce a suitable charge mixture into the inside of the crucible in which I have previously provided by any suitable means a fused cyanid volving screw into the fused cyanid mass at a rate proportional to the development of heat generated by the passage of the electric so that the charge introduced, and its decomposition mass heated to about 1400 C. The cold charge is fed by the reproducts. will become heated to substantiall 1400 C. before the gaseous products wi l have reached and broken through the surface of the fused mass. According to my discoveries, gaseous sodium and nitrogen at a temperature of about 1400" C. contacted with calcium carbid or free calciumand carbon will avidly combine to form calcium sodium cyanid, stable at this temperature. The calcium sodium cyanid, mixed with the fused mass in the furnace may be removed from the furnace through a tap-hole at the bottom of the furnace or 'at a level higher up in the crucible, either continuously or intermittently, always leaving in the crucible, however, a sufficient amount of fused mass to enable the above operations to be carried out in an efficient manner.

Obviously, the method herein described can, if desired, be applied to any of the reactions shown in my aforesaid co-pending application, and to similar reactions.

What I claim is:

1. The process of producing cyanid which consists in providing a fused cyanid mass at about 1 400 (1., feeding beneath'the surface thereof calcium cyanamid and a suitable source of sodium at such a rate that volatile elements formed between a red heat and 1400 C. will be heated to about 1400 C. and become contacted with non-volatile materials in the said fused mass, thereby reacting to form cyanid, removing such cyanid mixed with the said fused mass, and rapidly cooli 2. The process of producing cyanid'whi i consists in providing a fused cyanid mass at about 1400 C., feeding beneath the surface thereof calcium cyanamid and sodium at such a rate that the elementary nitrogen and gaseous sodium formed between a red heat and 1400 C. will be heated to about 1400- C. and become contacted with the residual non-volatile materials inthe said fused mass, thereby reacting to form cyanid, removing such cyanid mixed with the said fused mass, and rapidly cooling.

3. The process of producing cyanid which consists in providin a fused cyanid mass at about 1400 G., fee ing beneath the surface thereof calcium cyanamid and sodium cyanid at such a rate that the elementary nitrogen and sodium formed between a red heat and 1400 C. will be heated to about/1400 C. and become contacted with the residual non-volatile materials in the said fused mass, thereby reacting to form cyanid removing such cyanid mixed with the said fused mass, and rapidly coolin 4. The process of producing cyanid which consists in providing a fusedcyanid mass at about 1400 C., feeding beneath the surface thereof crude calciu'mcyanamid'and sodium chlorid at such a rate that the elementary nitrogen and sodium formed between a red heat and 1400" C. will be heated to about 1 rapidly cooling.

1400" 0. and become contacted with the residual non-volatilematerials in the said fused mass, thereby reacting to form cyanid, removing such cyanid mixed with the said fused mass, and rapidly cooling.

5. The process of producing cyanidwhich consists in providing a fusedcyanid mass at about 1400" 0., feeding beneath the surface thereof crude calcium cyanamid, sodium car 'bonate and a carbonaceous reducing agent at such a rate that the elementary nitrogen and sodium formed between a red heat and 1400" 0. will be heated to about 1400" 0. and become contacted with the residual non-vola-' tile materials in the said fused mass, thereby reacting to form cyanid, removing such cyanid, mixed with the said rapidly cooling;

6. The consists in providing a fused cyanid mass at about 1400" 0., feedingbeneath the surface thereof calcium carbid', sodium and nitrogen at such arate that the gaseous sodium and nitrogen will be heated to about 1400" 0. and I become contacted with the calcium carbid in the said fused mass at 1400" 0. thereby forming cyanid, removing, such cyanid, mixed with the said fused mass, and rapidly cooling. 7 The process of producing; cyanid which consists inprovidinga fused cyanid massat about 1400" 0., feeding beneath the surface thereof calcium carbid, sodium cyanid and nitrogen at such'a rate that the gases formed therefrom between a'red heat and 1400"'0.v

and the nitrogen'fed as such will be heated to about 1400" 0. and become contacted with the residual products of the said materials, thereby forming cyanid, removing such cyanid, mixed with process of producing cyanid which consists in providing a fused cyanid mass at 8. The

about 1400" 0., feeding beneath the surface I leased between a red heat and 1400 0.,and

thereof calcium carbid, sodiumschlorid and nitrogenat such a rate that the gases formed therefrom between a red heat and 1400" 0.

will beheated toabout 1400" 0. and become fused mass, and i the said fused mass, and

mass at 1400" '0. containing calcium carbid feeding beneath;

or free calcium and carbon, the surface thereof a suitable source. of sodium, and nitrogen, at such a rate that the sodium formed between the red heat and 1400" 0. and the nitrogen will be heated to about 1400" 0. and become contacted with the said calcium carbid or calcium and carbon in the said fused mass, thereby forming cyanid, removing such {cyanid mixed with thefsaid fused mass, and rapidly cooling.

12. In a process of producing crude calcium sodium cyanid in afused mass from suitable -materials at about 1400 0'. the method of preventing loss of volatile elements while heating'the materials from a elements will be heated to about 1400" 0. in-

the, said fused mass, thereby forming a fused cyanid by combining with non-volatile ma- 7 'terials in the said fused mass.

In testimony whereof, I affix my signa- -ture.

' EDWARD J. PRANKE.

process ofproducing cyanid red heat to the said 1400" 0. which consists in introducingithe' materials producing such contacted with the residualproducts of the i cyanid.;mixed with. the said consists inproviding a fused cyanid. mass at about 1400" 0., feeding beneath the surface i thereofcalcium carbid, sodium carbonate and nitrogen at such a rate that the sodium rethe nitrogen will be heated toabout 11400" 0;] and become contacted Withthe residual products of the saidmaterials in the said fused mass, thereby forming cyanid, remov-" ing. such "cyanid mixedfwith the said fused mass, andrapidly cooling.

10. The process of producing cyanidwhich l c nsists in providing ajfu'sed cyanid massiat 

